标题： recurrent nova T Pyxidis中物质转移率的加速下降 显示英文标题

标题： The Accelerating Decline of the Mass Transfer Rate in the Recurrent Nova T Pyxidis

摘要： recurrent nova T Pyxidis 自 1890 年以来爆发了六次，最近一次爆发是在 2011 年，经典新星爆炸之间的相对较短的复发时间表明 T Pyx 必须有一个以高吸积率存在的大质量白矮星。 人们认为，自 1890 年爆发以来，由于次星被炽热的白矮星加热的反馈回路，T Pyx 的物质转移速率非常大。 这个反馈回路正在缓慢关闭，减少了物质转移速率，从而解释了 T Pyx 的亮度从$\sim13.8$（1890 年之前）下降到 2011 年爆发前的 15.7： 我们分析了最新获得的$Hubble~Space~Telescope$（哈勃太空望远镜）远紫外和光学光谱，这些光谱是在 2011 年爆发后 12 年获得的，结果显示物质转移速率一直在稳步下降，并且现在已经比爆发前的水平低约 40%： 对于一个$\sim 1.0-1.4 M_\odot$质量的白矮星，倾角$50^\circ - 60^\circ$，消光$E(B-V)=0.30 \pm 0.05$和 Gaia DR3 距离$2860^{+816}_{-471}$约 pc 的情况，其速率为$\dot{M} \sim 1-3\times 10^{-7}M_\odot$/yr。 在2011年爆发之后的$\sim$十年里，质量转移速率的这种稳定下降，与来自国际紫外探索者（IUE）光谱的档案数据中更恒定的爆发前紫外连续辐射通量形成鲜明对比。 通量（即$\dot{M}$）在最近的$\sim$十年内的衰减率比自1890年至$\sim$年2010年观测到的快29倍。 反馈回路的关闭似乎正在加速，至少在它2011年爆发后的十年内是如此。 无论如何，我们的分析证实，T Pyx 正处于一个异常奇特且短暂的阶段。 显示英文摘要

摘要： The recurrent nova T Pyxidis has erupted six times since 1890, with its last outburst in 2011, and the relatively short recurrence time between classical nova explosions indicates that T Pyx must have a massive white dwarf accreting at a high rate. It is believed that, since its outburst in 1890, the mass transfer rate in T Pyx was very large due to a feedback loop where the secondary is heated by the hot white dwarf. The feedback loop has been slowly shutting off, reducing the mass transfer rate, and thereby explaining the magnitude decline of T Pyx from $\sim13.8$ (before 1890) to 15.7 just before the 2011 eruption. We present an analysis of the latest $Hubble~Space~Telescope$ (HST) far ultraviolet and optical spectra, obtained 12 years after the 2011 outburst, showing that the mass transfer rate has been steadily declining and is now below its pre-outburst level by about 40%: $\dot{M} \sim 1-3\times 10^{-7}M_\odot$/yr for a WD mass of $\sim 1.0-1.4 M_\odot$, an inclination of $50^\circ - 60^\circ$, reddening $E(B-V)=0.30 \pm 0.05$ and a Gaia DR3 distance of $2860^{+816}_{-471}$~pc. This steady decrease in the mass transfer rate in the $\sim$decade after the 2011 ourbutst is in sharp contrast with the more constant pre-outburst UV continuum flux level from archival international ultraviolet explorer (IUE) spectra. The flux (i.e. $\dot{M}$) decline rate is 29 times faster now in the last $\sim$decade than observed since 1890 to $\sim$2010. The feedback loop shut off seems to be accelerating, at least in the decade following its 2011 outburst. In all eventualities, our analysis confirms that T Pyx is going through an unusually peculiar short-lived phase.